1. Field of the Invention
This invention relates generally to safety closure and container assemblies, and is particularly concerned with an improvement in safety closure and container assemblies wherein it is necessary to provide a liquid or moisture-proof seal for the contents of the container.
2. Description of the Prior Art
In order to reduce the number of accidental poisonings resulting from young children having access to unsafe medicines, drugs, household chemicals and other products, there has been considerable activity in recent years towards the development of closures and containers in which a type of manipulation between the cap and container is required in order to gain access to the contents of a container that a young child is incapable of performing. For example, it has been found that young children are generally incapable of manipulating a cap mounted on a container with bayonet-type locking means, that is, a type of locking means that requires that the cap be pushed axially relative to the container and then rotated relative to the container in order to separate the cap from the container. The cap must be pushed axially toward the container against the biasing force of a spring in order to disengage the bayonet locking means. See, for example, Hedgewick U.S. Pat. No. Re. 27,156.
When the contents of the container is liquid, or is some substance that deteriorates in an atmosphere of high humidity, the closure must be capable of maintaining an adequate seal under a variety of conditions. The contents of the container, if liquid, may require vigorous shaking before being used, or the contents may be of the type that causes a pressure buildup within the container over a period of time. A tight seal is also necessary in order to prevent the undesired escape of the contents from the container, and because the entrance of moisture into the container may cause deterioration of the contents.
In order to maintain a good seal against the entrance or escape of moisture, it is desirable to be able to provide a seal that projects into the mouth of the container and engages the inner surface of the container mouth with a tight fit. While the spring force on the cap should be sufficient to prevent children from gaining access to the contents, it should not be so great as to make it unduly difficult for adults to manipulate the cap. Accordingly, a tight seal must be maintained by the closure without at the same time making it too difficult for adults to manipulate the closure. Since the closure must be applied to and removed from the container many times, the spring member must be capable of many cycles of deflection and relaxation without rupture. Furthermore, the construction of the closure and spring member must be such that the seal is firmly pressed against the container rim and the inner surface of the mouth of the container when the closure is placed on the cap and locked in position.
Hedgewick et al U.S. Pat. Nos. 3,478,911 and 3,485,403 illustrate safety cap and container assemblies wherein a flat disk overlies the container rim and is held captive in the cap by the bayonet lugs of the cap. In the construction illustrated in the latter Hedgewick et al patents, the flat disk is pressed against the container rim by elements formed integrally with and projecting from the end wall of the caps of the closure assemblies.
In Nichols U.S. Pat. No. 3,072,276, a closure assembly is illustrated in which a cap having bayonet lugs includes a plastic disk member which is dished at its center with the thickened periphery of the disk member overlying the bayonet locking lugs of the cap. An axially depending flange is received in the mouth of the container. A post projects integrally upwardly from the disk to engage the end wall of the cap and to cause the disk to deflect when the cap is applied to the container, the post projecting from the central axis of the disk.
Bugla U.S. Pat. No. 3,432,065 and Hedgewick and Bauer U.S. Pat. No. 3,753,510 disclose closure assemblies wherein biasing and sealing members are secured to the end wall of a safety cap by interconnecting members formed on the spring member and the end wall of the respective safety caps.
Bauer U.S. Pat. No. 3,623,623 illustrates a safety package wherein a spring and sealing member is secured to the container, the spring member having an axial opening through which the contents of the container can be dispensed.